The development leaves surfers who click on Google's picture of the day at risk of being exposed to sites that run fake security scans, before strong-arming users into buying worthless software in order to clean-up non-existent security risks

Scammers have been manipulating the search engine ranking of terms in the news to promote scamware portals for months. In the latest twist to this wheeze, fraudsters poisoned the sites offered up to surfers who clicked on Google's front-page Doodle sketch, dedicated to the 150th anniversary of birth of the creator of the Esperanto language, L. L. Zamenhof, on Tuesday.

Tainted results appeared among the top five to 10 search results for people who clicked on the Google doodle link on Tuesday, according to security researchers at Barracuda Networks. "Poisoning as a trend is nothing new, but in this particular case, it's a search where you actually click on Google's logo and you get results back from sites where half of the links have been compromised," Dave Michmerhuizen, a research scientist at Barracuda Networks, toldMacWorld.

Google, which stated other search engines are also targeted by black hat search engine optimisation techniques, said most of the tainted links were quickly removed from its index. Google uses a combination of continuously-refined automated and manual processes to clean-up its index, a spokesman for the search engine giant added.

Google and security researchers are in a continuous battle against distributors of rogue anti-virus scanners, one of the most prevalent information security threats contaminating the internet at present. FBI estimates out this week suggest that the scareware market brought in $150m in illicit income over an unspecified period.

An FBI Internet Crime Complaint Centre (IC3) advisory on the scareware menace can be found here. ®